import 'dart:async';
import 'dart:io' show Platform;
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:permission_handler/permission_handler.dart';
import '../../core/app_colors.dart';
import '../../core/navigation_provider.dart';
import '../../providers/auth_provider.dart';
import '../../providers/omron_device_provider.dart';
import '../../services/omron_ble_service.dart';

class DeviceScanPage extends ConsumerStatefulWidget {
  const DeviceScanPage({super.key});
  @override ConsumerState<DeviceScanPage> createState() => _DeviceScanPageState();
}

class _DeviceScanPageState extends ConsumerState<DeviceScanPage>
    with SingleTickerProviderStateMixin {
  final _results = <ScanResult>[];
  bool _scanning = false;
  String? _connectingId;
  StreamSubscription? _scanSub;

  bool _connected = false;
  String _deviceName = '';
  bool _readingReceived = false;
  int? _systolic, _diastolic, _pulse;
  StreamSubscription? _readingSub;
  StreamSubscription? _bleConnSub;

  late AnimationController _pulseCtrl;
  late Animation<double> _pulseAnim;

  @override void initState() {
    super.initState();
    _pulseCtrl = AnimationController(vsync: this, duration: const Duration(milliseconds: 1200));
    _pulseAnim = Tween(begin: 0.8, end: 1.4).animate(CurvedAnimation(parent: _pulseCtrl, curve: Curves.easeInOut));
    _pulseCtrl.repeat(reverse: true);

    _scanSub = FlutterBluePlus.scanResults.listen((list) {
      if (!mounted) return;
      final bpList = list.where((r) => OmronBleService.isBpDevice(r)).toList();
      setState(() { _results.clear(); _results.addAll(bpList); });
    });
    _start();
  }

  @override void dispose() {
    _pulseCtrl.dispose();
    _scanSub?.cancel();
    _readingSub?.cancel();
    _bleConnSub?.cancel();
    FlutterBluePlus.stopScan();
    super.dispose();
  }

  Future<void> _start() async {
    setState(() { _scanning = true; _connected = false; });
    _results.clear();

    await [Permission.bluetoothScan, Permission.bluetoothConnect].request();

    if (Platform.isAndroid) {
      final locStatus = await Permission.locationWhenInUse.serviceStatus;
      if (locStatus != ServiceStatus.enabled && mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('请先打开GPS定位，否则无法扫描蓝牙'), backgroundColor: AppColors.warning),
        );
      }
    }

    final adapterState = await FlutterBluePlus.adapterState.first;
    if (adapterState != BluetoothAdapterState.on) {
      try { await FlutterBluePlus.turnOn(); } catch (_) {}
    }

    try { await FlutterBluePlus.stopScan(); } catch (_) {}
    await FlutterBluePlus.startScan(
      timeout: const Duration(seconds: 30),
      androidScanMode: AndroidScanMode.lowLatency,
    );

    Future.delayed(const Duration(seconds: 30), () {
      FlutterBluePlus.stopScan();
      if (mounted) setState(() => _scanning = false);
    });
  }

  Future<void> _connect(ScanResult r) async {
    setState(() => _connectingId = r.device.remoteId.toString());
    FlutterBluePlus.stopScan();
    _scanSub?.cancel();

    try {
      final ble = ref.read(omronBleServiceProvider);
      await ble.connect(r.device);
      final name = r.advertisementData.localName.isNotEmpty
          ? r.advertisementData.localName
          : (r.device.platformName.isNotEmpty ? r.device.platformName : '血压计');

      await ref.read(omronDeviceProvider.notifier).bind(r.device.remoteId.toString(), name);

      _bleConnSub = r.device.connectionState.listen((s) {
        if (s == BluetoothConnectionState.disconnected && mounted) {
          _readingSub?.cancel();
          ref.read(omronBleServiceProvider).disconnect();
          if (_readingReceived) {
            popRoute(ref);
          } else {
            setState(() { _connected = false; });
            _start();
          }
        }
      });

      _readingSub = ble.readings.listen((reading) async {
        debugPrint('[PAGE] 收到: ${reading.systolic}/${reading.diastolic}');
        if (mounted) {
          setState(() {
            _readingReceived = true;
            _systolic = reading.systolic;
            _diastolic = reading.diastolic;
            _pulse = reading.pulse;
          });
          try {
            await ref.read(apiClientProvider).post('/api/health-records', data: reading.toHealthRecord());
            await ref.read(omronDeviceProvider.notifier).onReading(reading);
          } catch (e) { debugPrint('[PAGE] 上报失败: $e'); }
          Future.delayed(const Duration(milliseconds: 1500), () {
            if (mounted) popRoute(ref);
          });
        }
      });

      if (mounted) {
        setState(() {
          _connected = true;
          _deviceName = name;
          _connectingId = null;
          _readingReceived = false;
        });
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('连接失败: $e'), backgroundColor: AppColors.error),
        );
        _start();
      }
    }
  }

  @override Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      appBar: AppBar(
        backgroundColor: Colors.white,
        elevation: 0,
        title: Text(_connected ? _deviceName : '添加设备', style: const TextStyle(color: AppColors.textPrimary)),
        leading: IconButton(
          icon: const Icon(Icons.arrow_back, color: AppColors.textPrimary),
          onPressed: () {
            if (_connected) ref.read(omronBleServiceProvider).disconnect();
            popRoute(ref);
          },
        ),
      ),
      body: _connected ? _buildConnected() : _buildScan(),
    );
  }

  // ── 扫描视图 ──
  Widget _buildScan() => Column(children: [
    if (_scanning && _results.isEmpty) Expanded(child: _buildScanningCenter()),
    if (!_scanning && _results.isEmpty) Expanded(child: _buildScanningCenter()),
    if (_results.isNotEmpty)
      Expanded(
        child: ListView.builder(
          padding: const EdgeInsets.all(16),
          itemCount: _results.length,
          itemBuilder: (_, i) => _buildTile(_results[i]),
        ),
      ),
    if (!_scanning)
      Padding(
        padding: const EdgeInsets.all(16),
        child: SizedBox(width: double.infinity, child: OutlinedButton.icon(
          onPressed: _start,
          icon: const Icon(Icons.refresh),
          label: const Text('重新扫描'),
          style: OutlinedButton.styleFrom(
            foregroundColor: AppColors.primary,
            side: const BorderSide(color: Color(0xFFE5E7EB)),
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(14)),
            padding: const EdgeInsets.symmetric(vertical: 14),
          ),
        )),
      ),
  ]);

  Widget _buildScanningCenter() => Center(
    child: Column(mainAxisSize: MainAxisSize.min, children: [
      Stack(alignment: Alignment.center, children: [
        AnimatedBuilder(
          animation: _pulseAnim,
          builder: (_, child) => Container(
            width: 80 * _pulseAnim.value, height: 80 * _pulseAnim.value,
            decoration: BoxDecoration(
              shape: BoxShape.circle,
              color: AppColors.primary.withOpacity(0.08),
            ),
          ),
        ),
        Container(
          width: 64, height: 64,
          decoration: BoxDecoration(
            color: const Color(0xFFF0F0FF), borderRadius: BorderRadius.circular(20),
          ),
          child: const Icon(Icons.bluetooth_searching, size: 32, color: AppColors.primary),
        ),
      ]),
      const SizedBox(height: 20),
      Text(_scanning ? '正在搜索蓝牙设备...' : '未发现设备', style: const TextStyle(fontSize: 16, color: AppColors.textHint)),
      const SizedBox(height: 8),
      Text(_scanning ? '请确保血压计处于通信模式' : '点击下方按钮重新搜索', style: const TextStyle(fontSize: 13, color: Color(0xFFCCCCCC))),
    ]),
  );

  // ── 已连接视图 ──
  Widget _buildConnected() => Center(
    child: Padding(
      padding: const EdgeInsets.all(32),
      child: Column(mainAxisSize: MainAxisSize.min, children: [
        AnimatedContainer(
          duration: const Duration(milliseconds: 500),
          width: 100, height: 100,
          decoration: BoxDecoration(
            color: _readingReceived ? const Color(0xFFD1FAE5) : const Color(0xFFF0F0FF),
            borderRadius: BorderRadius.circular(32),
          ),
          child: Icon(
            _readingReceived ? Icons.check_rounded : Icons.bluetooth_connected,
            size: 48,
            color: _readingReceived ? const Color(0xFF10B981) : AppColors.primary,
          ),
        ),
        const SizedBox(height: 24),
        Text(_readingReceived ? '测量完成' : '设备已连接', style: const TextStyle(fontSize: 22, fontWeight: FontWeight.w700, color: AppColors.textPrimary)),
        const SizedBox(height: 8),

        if (_readingReceived) ...[
          Row(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.end, children: [
            Text('$_systolic', style: const TextStyle(fontSize: 56, fontWeight: FontWeight.w800, color: AppColors.textPrimary, height: 1)),
            Padding(padding: const EdgeInsets.only(bottom: 10), child: Text('/', style: TextStyle(fontSize: 24, color: AppColors.textHint.withOpacity(0.5)))),
            Text('$_diastolic', style: const TextStyle(fontSize: 56, fontWeight: FontWeight.w800, color: AppColors.textPrimary, height: 1)),
            const SizedBox(width: 8),
            Padding(padding: const EdgeInsets.only(bottom: 12), child: Text('mmHg', style: TextStyle(fontSize: 15, color: AppColors.textHint))),
          ]),
          if (_pulse != null)
            Padding(
              padding: const EdgeInsets.only(top: 8),
              child: Container(
                padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 6),
                decoration: BoxDecoration(color: const Color(0xFFEFF6FF), borderRadius: BorderRadius.circular(20)),
                child: Text('脉搏 $_pulse bpm', style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w500, color: AppColors.primary)),
              ),
            ),
          const SizedBox(height: 16),
          const Text('数据已自动同步', style: TextStyle(fontSize: 14, color: AppColors.textHint)),
          const SizedBox(height: 8),
          const SizedBox(width: 24, height: 24, child: CircularProgressIndicator(strokeWidth: 2, color: AppColors.primary)),
        ] else ...[
          const Text('请按下血压计的开始键进行测量', style: TextStyle(fontSize: 15, color: AppColors.textHint)),
          const SizedBox(height: 32),
          AnimatedBuilder(
            animation: _pulseAnim,
            builder: (_, __) => Container(
              width: 48, height: 48,
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                border: Border.all(color: AppColors.primary.withOpacity(0.3), width: 2),
              ),
              child: Center(
                child: Transform.scale(
                  scale: _pulseAnim.value,
                  child: Container(width: 12, height: 12, decoration: const BoxDecoration(shape: BoxShape.circle, color: AppColors.primary)),
                ),
              ),
            ),
          ),
        ],
      ]),
    ),
  );

  // ── 设备列表项 ──
  Widget _buildTile(ScanResult r) {
    final isConnecting = _connectingId == r.device.remoteId.toString();
    final name = r.advertisementData.localName.isNotEmpty
        ? r.advertisementData.localName
        : (r.device.platformName.isNotEmpty ? r.device.platformName : '未知设备');

    return Container(
      margin: const EdgeInsets.only(bottom: 8),
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: const Color(0xFFEEEEEE)),
      ),
      child: Row(children: [
        Container(
          width: 44, height: 44,
          decoration: BoxDecoration(color: const Color(0xFFF0F0FF), borderRadius: BorderRadius.circular(12)),
          child: const Icon(Icons.bluetooth, size: 22, color: AppColors.primary),
        ),
        const SizedBox(width: 12),
        Expanded(child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
          Text(name, style: const TextStyle(fontSize: 16, fontWeight: FontWeight.w600, color: AppColors.textPrimary)),
          const SizedBox(height: 2),
          Text('${r.device.remoteId}  ·  信号: ${_rssiLabel(r.rssi)}', style: const TextStyle(fontSize: 12, color: AppColors.textHint)),
        ])),
        if (isConnecting)
          const SizedBox(width: 24, height: 24, child: CircularProgressIndicator(strokeWidth: 2))
        else
          GestureDetector(
            onTap: () => _connect(r),
            child: Container(
              padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
              decoration: BoxDecoration(color: AppColors.primary, borderRadius: BorderRadius.circular(12)),
              child: const Text('连接', style: TextStyle(fontSize: 14, fontWeight: FontWeight.w600, color: Colors.white)),
            ),
          ),
      ]),
    );
  }

  String _rssiLabel(int r) {
    if (r > -55) return '强';
    if (r > -70) return '中';
    return '弱';
  }
}